Barcode printer and SAAS

My company recently developed a small file management web app for a law firm. And we have a problem. The application was supposed to be deployed on their own internal server. But now, they want us to host it. That wouldn't be a problem if we were not using a small .bat script, launched with PHP's exec() function, for barcode printing. The printer needs some specific format instructions, and we need the printing to be done silently.

So here's my question : is there a way to print on this device from our application ? The main problem is that our b开发者_JS百科oss wants to have nothing installed on their server, not even a minimal C# app or something I could have used to listen to calls from the main web app. I guess the solution must be on the client side. Javascript ? A Java applet ?

Thanks for your answers, and sorry for my bad english.

I'm not sure what type of printer you're using but I know Dymo has a nice SDK which will let your print from the web using javascript. I use it for addresses within my contact manager (little PHP/MySQL thinger.) Select contact, click button, label pops out. Some other fella is using the same idea for a wine cataloging system where it prints production information to a label for the bottles.